3 of 4 A Copper Wire Rh Switch Step 2: Adjust the rheostat Rn and record the value of voltage and current. Repeat this five times. Calculate the average resistance. Step 3: Using the known value of the radius of the cylindrical wire and the length of the wire, calculate the area A. Step 4: Calculate the resistivity using eq. 1. Step 5: Repeat the experiment for copper wire of different radius. Step 6: Find the percent error in your resistivity calculation using known values from the text book. Useful information: p{Cu}= 1.68 x 10-8 0.m; p {Cu-ni-alloy}= approx 5x10-7 0.m Gauge 22 - diameter 0.64 mm; Gauge 28 > diameter 0.32 mm Physics Department, Tuskegee University DATA TABLES Copper 1 Measurement Current Voltage Resistance (V/1) Average R 1. 2. 3. 4. 5. Resistivity (Pexp). Copper 2 Measurement Current Voltage Resistance (V/I) Average R 1. 2. 3. 4. 5 . Resistivity (Pexp). Known Resistivity of copper (From Book) Pknown- % Error Calculation